NTDETECT FAILURE issue with my HP Server

Hi,
I have Hp Proliant ML-370 with SBS 2003, RAID Level 5, ISA Server 2004, AD, SQL 2000, Exchange server 2003, Symentec End 2 End Protection.
The problem is, when i start's the server it shows "NTDETECT FAILURE" with black screen. I have tried allot to resolve it, with SBS Repair console, but its worthless. Can you guys help me to findout resolving this issue. Thanks.
Adeel Khan